National Credit Act maximum interest rate API
The maximum lawful interest rate for every South African credit agreement type under National Credit Act Regulation 42 Table A, as cited JSON. The margins have been fixed since 6 May 2016 (GN R.1080, GG 39379) and the computed caps move whenever the SARB changes the repo rate.
The critical rule the endpoint encodes: the maximum rate is fixed at the repo rate in force on the date the agreement was concluded, and does not move with later repo changes. Get that wrong and a lawful agreement looks unlawful, or the reverse.
Series
GET /v1/nca-max-rates
Maximum lawful interest rates per credit type under National Credit Act (NCA) Regulation 42 Table A, computed at the current repo rate, plus the in duplum rule and service fee cap.
$0.005 per call · updates: per SARB repo change (margins fixed since 2016) · effective 2026-05-29 · history at /v1/nca-max-rates/history ($0.01)
GET /v1/repo-prime
SARB repo rate and prime lending rate, South Africa's benchmark interest rates, with last MPC change date.
$0.005 per call · updates: per SARB MPC meeting (~every 2 months) · effective 2026-05-29 · history at /v1/repo-prime/history ($0.01)
GET /v1/sars-interest-rates
Official rate of interest (fringe benefits, s7C loans), SARS interest on outstanding taxes and refunds, and the prescribed rate of interest for legal and judgment debts.
$0.005 per call · updates: per SARB repo change (formula-linked) + SARS/gazette publications · effective 2026-07-01 · history at /v1/sars-interest-rates/history ($0.01)
Calculators
GET /calc/nca-max-rate
Maximum lawful interest rate for a credit agreement under NCA Regulation 42 Table A, at the current or a given repo rate.
Parameters: type, repo, subsequent_loan
$0.01 per call · example: /calc/nca-max-rate?type=unsecured
How agents pay
No account, no API key. Paid endpoints reply HTTP 402 with exact payment requirements; an x402 client pays USDC on Base (about two seconds to settle) and retries automatically. Invalid input is rejected free with a 400 before any payment is challenged. See the x402 quickstart.
Questions
- What is the maximum interest rate allowed in South Africa?
- It depends on the credit type. Regulation 42 Table A sets fixed margins over the repo rate: mortgage agreements repo plus 12 percent, credit facilities repo plus 14, unsecured credit repo plus 21, developmental credit repo plus 27 and other agreements repo plus 17, all per year. Short-term credit is capped per month rather than per year, and incidental credit at 2 percent per month. GET /v1/nca-max-rates returns all of them computed at the current repo rate.
- Which repo rate applies to an existing agreement?
- The one in force on the date the agreement was concluded. The cap is fixed at inception and does not track later MPC decisions. GET /calc/nca-max-rate?repo= computes the cap at any given repo rate for exactly this reason.
- What is the in duplum rule?
- Under section 103(5) of the NCA, while a consumer is in default, interest, fees and the other section 101(1)(b) to (g) charges may not in aggregate exceed the unpaid principal balance as at the date of default. The rule is carried on the response rather than left for the caller to remember.
- Is the monthly service fee capped too?
- Yes, and the current cap is returned alongside the interest caps, since an agreement can be lawful on rate and unlawful on fees.
- Can I get a lawful or unlawful verdict rather than the caps?
- Yes, from the sister service: verza.dev runs a full credit-agreement lawfulness check that returns a verdict, the exact cap, any excess and the workings, using the repo rate at the conclusion date. See verza.dev, which composes its verdict from this same audited data.
Related
South African repo and prime rate API South Africa fuel price API SARS income tax tables API South Africa VAT API and free calculator South African public holidays API